Download video files from varied sources, just type in the URL in the box in the homepage (http://keepvid.com). Drag this keepvid bookmarklet (javascript:document.location='http://keepvid.com/?url='+escape(window.location);) to download the video without moving anywhere else. Supports tens of video sites. Here's another site (http://javimoya.com/blog/youtube_en.php) similar to keepvid.

Kissyoutube - Keep it super simple (http://www.kissyoutube.com/)

Just prefix the word kiss before the original video URL. For example, if the URL is http://www.youtube.com/watch?abcd, use the URL http://www.kissyoutube.com/watch?abcd
to download the .flv file.

Use Firefox? Then get this extension right here (https://addons.mozilla.org/en-US/firefox/addon/2254). When you're on a page with the video, right click anywhere on the page and select 'Unplug' or press the 'Unplug' button on your browser. It will list the available media files which you can then download on to your computer.

Get this extension here (https://addons.mozilla.org/en-US/firefox/addon/2390) and just start downloading. Supports over 60 sites. Click on the small VideoDownloader icon on the status bar for robbing the video off the page.

Drag the bookmarklets available on these page onto your browser's toolbar, click when you're on the page, and it's done. Download the video this easy way. This page (http://1024k.de/bookmarklets/video-bookmarklets.html) has got tens of bookmarklets for you.

Youtube Downloader - video.qooqle.jp (http://video.qooqle.jp/dl/)

This is again simple: put the URL in the text box. One more downloader similar to this one with some help for you is here (http://youtubevideosdownload.com/download/).

YoutubeX (http://www.youtubex.com)
This is another site, but it was slow on my computer. Try it here (http://www.youtubex.com).

Viloader.net (http://www.viloader.net/)

The interface is cool, and nothing special. Just another download site.

DownThisVideo (http://downthisvideo.com/)

One more on the block with some recent tags laid out.

These are some ways to download videos from your favourite sites, try them, and stick to any of them. If you know any better tools, inform people in the comments. http://feeds.feedburner.com/~f/shankarstechblog?i=3IPD4EAp</img> (http://feeds.feedburner.com/~f/shankarstechblog?a=3IPD4EAp) http://feeds.feedburner.com/~f/shankarstechblog?i=YMkY8tAe</img> (http://feeds.feedburner.com/~f/shankarstechblog?a=YMkY8tAe) http://feeds.feedburner.com/~f/shankarstechblog?i=0LmAkSfG</img> (http://feeds.feedburner.com/~f/shankarstechblog?a=0LmAkSfG)

Read the full post (http://feeds.feedburner.com/~r/shankarstechblog/~3/107717912/keepvid.html)